LH Thomson Dropper Post – Unboxed, Weighed & First Impressions!

After visiting LH Thomson’s factory and talking with Dave Parrett in depth about their upcoming adjustable height dropper seatpost’s internals, it seemed clear they were on to something.

We covered the internals tech pretty well in that post, but the short of it is this: Rather than rely on mechanical clamps or an air chamber, Thomson’s post uses an oil cartridge to control height and nitrogen shock to return it to full height. The remote lever pulls a cable, which rotates a graduated cam that presses a release valve for the oil cartridge. As it’s depressed, oil is allowed to flow between the upper and lower chambers. Release the lever and it closes the valve. Since oil won’t compress, the post sticks in whatever position it’s in when you let go of the lever. If your weight’s on it, it’ll drop. If not, the nitrogen shock pushes it back up.

Drop in for our first impressions on how that all comes together, plus actual weights and more…

It’s important to note that this is a late stage prototype, not quite production. Most it is what you’ll see when they hit your local bike shop save that it’ll likely have different cable and housing. That said, it’s pretty darn close, and this particular one is Parrett’s personal post that he’s been trashing testing for a while. What’s impressive about that is there there’s zero play in it and the action is as smooth as can be.

The 400mm 30.9 post with cable, housing and remote lever comes in at 586g.

The drop and rise rate is preset, but you can control it by limiting how much you depress the lever.

The saddle clamp is classic Thomson.

The cable pulls a lever that actuates the cam underneath the saddle clamp’s lower cradle. If you routinely ride in muddy or wet weather, it’s probably not a bad idea to remove your saddle completely every couple months and clean out the top of the post (video in the Factory Tour post shows this close up). These pics show starting position (left) and with the lever fully pressed (right). There’s not a lot of movement, and that’s one of the reasons why it’s a little difficult to control the rate of descent or ascent by feathering the lever.

The post has 125mm of height adjustment, dropping all the way to the neck of the stanchion.

A plastic cable guide spins freely around the top of the outer post. This helps the cable housing move freely as the post goes up and down. A fixed guide might cause unnatural bends in the housing on a post like this, so it’s a good fix. We’d all like to see dropper posts with the cable entry at the base rather than the top, but at least cable management has been addressed.

The lever is machined in typical Thomson style and anodized black to match their stems and posts. It pulls a standard shift cable (or, at least, this prototype does…that’s one item they’re still finalizing), and action is smooth. It should ship with 60″ of cable and housing, and like any bike cable and housing, can be cut to fit. Just be sure to measure with the post all the way up and with enough slack at the front to allow for complete steering rotation. Parrett says the only catch with installation is not putting too much tension in the cable, which can result in the seat raising or lowering on it’s own, however slowly. We found one other catch:

While the lever is gloriously minimal, it also uses a straight cable exit, which can make placement either interesting or challenging. Shown here is the more likely placement, cable running forward with lever being depressed down and behind the bar. It’s not a bad spot, but putting it outside (from the stem, between the grip) of the shifter/lever clamps means the cable is running directly over the brake lever. It’s close enough to the lever’s pivot point not to interfere, but depending on whether you’re using i-Spec or Matchmaker clamps or not, you may have to jockey for position with the shifter levers.

Angle it to far down and it could tap the top of the shifter’s thumb lever. You could run it inboard of the shifter/brake clamps, but that moves it pretty far away from your hands.

The alternative is to flip it and set it up so you have to push it forward, but that absolutely requires placement inboard of the brake/shifter clamps to avoid having the cable interfere with your shift levers. Plus, it just doesn’t look right. None of these concerns are a deal breaker, just worth mentioning as you’ll likely want to have an extra 10 minutes or so to fiddle with the lever placement during install.

On the plus side, the attention to detail is exactly what you’d expect from Thomson. The mounting bolt threads into a captured swiveling nut, which eliminates any stresses on the bolt or the clamp, which should improve longevity and strength.

PERFORMANCE

Thomson knew they’d have to hit a home run with this one, and first impressions suggest they did. Even having received a well used test post, it’s a telling sign that its function remains flawless. It slides up and down smoothly and easily with no signs of stiction. There’s no noise when moving and minimal “clunk” when it hits bottom or tops out. You can control the speed, but there’s so little lever movement it’s tough. It doesn’t matter, the speed is good – dropping and rising fast enough but not so fast that you a) feel like you’re falling out of a chair or b) worried it’ll damage your sensitive parts on the way up.

We’ll flog this one for as long as David will let us have it (or until he swaps it out for a true production unit) and report back when appropriate. If you’ve been holding out for this thing, it should be available this month and personally I wouldn’t hesitate.

FUTURE DEVELOPMENTS

As Parrett told us before, they’re working on additional sizes and versions. The latest word is that progress is being made on the 27.2 version and the road-oriented Pavé dropper post. As for that Bluetooth remote control, well, time will tell.

Comments

cool. obviously I would like to touch it myself, but I have doubts about the lever.

Dale - 04/10/13 - 8:56pm

Someone’s gonna get a nitro blast up the anoos.

Greg - 04/10/13 - 9:17pm

” Rather than rely on mechanical clamps or an air chamber, Thomson’s post uses an oil cartridge to control height and nitrogen shock to return it to full height.”
nitrogen=air chamber

Hill - 04/10/13 - 9:18pm

Nice bike

JR - 04/10/13 - 9:22pm

Niner making seats now?

yesplease - 04/10/13 - 10:11pm

JR did you miss the WTB logos all over it? WTB “makes” saddles for Troy Lee, Niner, etc etc…..

SomeGuy - 04/10/13 - 10:24pm

Hmm…looks a lot like the Giant dropper post, except heavier and still not available.

nparker94 - 04/10/13 - 10:40pm

It looks sweet and awesome, but the distributor QBP (Quality Bicycle Products) is selling it for $600. Even though it is Thompson and it will probably last longer than i will, i still think its way too much for a dropper seat post. I’m gonna stick with the tried and true Reverb.

Morgan - 04/10/13 - 10:43pm

Greg, they are talking about how the post holds the height position. There are two different chamber types in the post. One for the maintaining the height (hydraulic), and the other is just to return the saddle back up (nitrogen).

Jeb - 04/11/13 - 1:03am

This thing is new and already 3 years behind the times. Exposed cable…..really? A lever that will fillet your knee open at the slightest touch, did they even ride this thing in the dirt?

Chew - 04/11/13 - 1:37am

@Jeb – a few inches of electrical or duct tape would seal that cable off no problem. If the post is half as reliable as other thomson products it’s a winner in my book. The lever looks good to me too; at least no worse than the reverb lever which is hard to place with shimano controls and extremely fragile. I do like my reverb though and won’t be swapping it out as long it continues to work as well as it has. Rock Shox has great CS too!

Andre - 04/11/13 - 2:17am

Someone needs to me up for the challenge to make something with carbon tubes, with way lighter clamps and something under 300g.

bc - 04/11/13 - 7:02am

carbon no like slidey. Is make go break break.

Igor - 04/11/13 - 7:27am

I totally hate my 27,2 seatpost size right now. Not that I could afford this post right now, but even when I will I’ll still have to buy a new bike first. 4 inches of drop is not enough.

mateo - 04/11/13 - 8:47am

@nparker – first off… QBP isn’t “the” thomson distributor. They’re available from many US distributors. secondly, neither Q nor any other distributor is selling it for $600 at wholesale.

juanp - 04/11/13 - 9:01am

@nparker – mateo is right, QBP is not ‘the’ Thompson distributor. And 5 seconds on the magical thing called the internet brings up an MSRP of $450, not $600.

Jimjam - 04/11/13 - 9:33am

Nice, always a fan of Thomson

Jeff - 04/11/13 - 9:58am

Are they making it in the USA? I hate spending that much $ on something made abroad.

Nate - 04/11/13 - 11:27am

This thing is going to crush the reverb and other posts. The other posts have play, you can’t have them somewhere in the middle of the travel, i.e you have to be all the way up or down, and you KNOW they’re not as quality a product. And yes, it’s made in the USA at the Thomson factory, the only thing that isn’t is the cartridge.

I don't think so. - 04/11/13 - 11:35am

I don’t think the KS Lev has anything to worry about.

Jeff - 04/11/13 - 1:05pm

HUH? What happened to the 450gm weight they were posting in all the pre-release press?

bin judgin - 04/11/13 - 2:07pm

$1000 seatpost eh?

The entire internals that take care of the actual mode of dropping aren’t made in house, correct? Too bad.

Whaaaaaat - 04/12/13 - 3:28pm

wow Nate… I bet you never tried the Reverb.. you can stop it ANYWHERE within it’s travel and it’s solid. Plus Thompson is “quality” until the fail point, then it shatters like a glass bottle. Thompson is just a boatload of Hype, Fanboys, and MadeintheUSA smoke up the a$&.

Watch how many fan boys get all riled up by this. LOL

Erik - 04/13/13 - 9:29am

I was waiting 9 months for this, was going to replace my KS. As the weight and price went up and i started to realize the concerns with the upward facing exposed cable/housing, my desire faded. Ended up with a Gravity Dropper LP Turbo, and have no regrets! GD is way lighter, fool proof, most reliable, custom settings, and made in the USA. Yes, the GD looks ugly, but function and weight cannot be beat. Price and being made in USA, were bonus. Sorry Thomson.

I’ve been hearing great stuff about the KS posts for the past three years. I ask riders about their experiences with KS and they’re always good. The cable interface is fixed (a real plus), the price is one of the most reasonable out there, and they’re one of the few manufacturers who make a 27.2…(I’m amazed at how many 27.2s are still out there).
Hey, many of the other posts are well-engineered, and real eye candy to boot! However their cost & durability keep the KS at the top of my list.

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